For patients that need to stay in bed for a long time, patients need to turn over with the aid of nurses regularly (e.g. once every two hours) in order to reduce the likelihood of suffering from the bedsore. However, since the patients' conditions are different, the medical care manner of turning over the patients every two hours may not be suitable for all the patients. Therefore, it is difficult for the nurses to accurately determine the best time for each of the patients to turn over, which brings about great inconveniences for the nursing work.